Cross polar performance characteristics of shaped gridded reflectors

The co and cross polar performance specifications in current satellite communications applications relating to dual gridded, shaped reflector systems are very demanding. In order to meet them, it is essential to possess a radiation pattern prediction capability which supports the practices of manufacture and test. The paper discusses work carried out at MMS UK Ltd. (Stevenage) which has resulted in the development of a software package, referred to as GRAPPA (GRidded Antenna Pattern Prediction Algorithm), which successfully predicts co and cross polar performance characteristics in dual gridded, shaped reflector systems. An established theory describing the effects of plane wave scattering from a thin wire grid has been combined with a physical optics analysis for shaped reflectors to produce an approximate hybrid theory which may be used, to good effect, to predict the radiation pattern characteristics of such reflector systems